Automobile heater



y 1942.- T. F. SPACKMAN' 2,290,299

' AUTOMOBILE HEATER Filed Dec, 23, 1959. Z'Sheets-Sheet'l July 21, 1942. T. F, SPACKMAN 2,290,299

AUTOMOBILE HEATER Filed Dec. 23, l939 2 Sheets-Sheet 2 az/mz Patented July 21, 1942 AUTOMOBILE HEATER Thomas F. Spackman, Chicago, lit, assignor to Stewart-Warner Corporation, ()hicago, llL, a corporation of Virginia Application December 23, 1939, Serial No. 310,711

3 Claims.

My invention relates generally to automobile heaters, and more particularly to an improved heat exchanger for-heaters of this type.

It is an object of the invention to provide an improved heat exchange device comprising essentially a single die cast element having a number of circuitous passageways extending therethrough.

A further object is to provide an improved heat exchanger for automobile heaters of the internal combustion type in which the core consists of a unitary die casting having generally parallel interconnected passageways extending therethrough. A further object is to provide an improved heat exchange device for automobile heaters which is simple in construction, may be economically manufactured, and which is eflicient in operation.

Other objects will appear from the following to suction of the intake manifold of the engine, the casting in having an outlet passageway 2 which communicates through a conduit 26 with the intake manifold 28. A compensator 30 having a Venturi-shaped passageway extending therethrough is adapted to be closed by a valve 32 formed at the end of the valve stem 34 which has an operating button 36 secured at the outer end thereof. The gases of combustion, when the description, reference being had to the accompanying drawings, in which:

Figure 1 is a fragmentary vertical sectional view of an automobile heater of the internal combustion type showing the improved heat exchange device;

Figure 2 is a transverse vertical sectional view taken on the line 22 of Fig. 1;

valve 32 is open, flow from the combustion chamber l2 through ports in a reigniter 38 and openings in a bafile 40 to the passageways in a heat exchanger casting 42. After passing through the circuitous passageways in this casting 42, the gases flow through the compensator 38, and hence to the intake manifold of the engine. Air. from the passenger compartment of the vehicle is forced downwardly over the heat exchange device by a fan M driven by a motor 46. Suitable electrical circuits controlled by a switch mechanism 48 are provided so that upon pulling the button 38 to open the valve 32, an igniter 50 of the resistance wire type is connected .in circuit so as to be heated-to incandescence, and thus Figures 3 and 4 are similar sectional views taken on the lines 3-3 and 4-4 respectively of Fig. 1;

Figure 5 is a fragmentary sectional view taken on theline 5-5 of Fig. 2; and (M Figure 6 is a developed sectional view taken on the circular line 66 of Fig. 4, and diagrammatically illustrating the manner in which the gases of combustion flow through the passageways.

Referring to Fig. 1, the heater in which the heat exchange device of my invention may be used advantageously comprises a combustion chamber casting l0 having a combustion chamber I2, to which a mixture of fuel and air provided by a carbureting device H3 is-supplied through a tube IS, the tube l6 having a sidewardly facing opening 18 adjacent a baflie 20 which partially obstructs'the flow of the combustible mixture to the combustion chamber I2. Fuel is supplied to the carbureting device Hi from a suitable reservoir 22, which may be the float bowl of the engine carburetor of the automobile upon which the heater is mounted, or

which may be a separate auxiliary fuel reservoir. The mixture supplied by the carbureting device [4 is drawn into the combustion chamber due 5 combustion chamber casting E0, the flanged end having an annular recess 54 to receive a compleignite the combustible mixture in the chamber 2. The switch mechanism 48 also includes a thermostatically controlled switch which connects the motor as to the source of power after the heat exchange device has attained a predetermined temperature, and also disconnects the igniter 50 from the source of current, usually the storage battery of the automobile.

The heater, as thus far generally described, is disclosed in greater detail in the co-pending application of Henry J. DeN. McCollum, Serial No. 120,523,1iled January 14,1937, which has matured into Patent No. 2,191,174 dated February 20, 1940. I

Referring now more particularly to the novel heat exchanger, the casting 32 is generally cylindricalin shapehaving an end flange 52, the outer face of which abuts against the end of the mentary projection 56 formed upon the casting Ill. The baflie 4D is held in place between the end of the projection 56 of the casting Ill .and a shoulder 58 formed at the end of the recess 5 As shown in Fig. 3, the baflie G0 has a relatively large opening 60 formed therein in com- 7 munication with a passageway 62 formed in the casting 42 and extending the full length thereof.

The rearward (left-hand) end of the walls of the pasageway 62 are provided with openings 62 connecting the passageway B'Zwith passageways 63 and 64 respectively. The forward ends of the and contract in an oscillatory manner.

pasageways 63 and 64 communicate with passageways 65 and 66 respectively through ports 66,

.while the rearward ends of the passageways 65 and 66 communicate with passageways 69 and 16 respectively through ports 12. The forward ends of the passageways 69 and III communicate with the passageway through the compensator 30 via ports 13 and I4. From the foregoing, it

will appear that gases of combustion flowing through the opening 60 in the baille plate," flow rearwardly through the passageway 62 and then divide, one part flowing to the compensator Illthrough pasageways 63, 65, and 69, while the other part flows to said compensator through pasageways 64, 66, and It.

In order to prevent so-called motor boating," the bailie 40 is provided with a pair of openings I5 and 16 which permit a small quantity of the gases of combustion to flow into the passageways'65 and 66 respectively. The admission of this small quantity of gas to these passageways eifectively counteracts a tendency, which might otherwise be present, for the gas to expand Such expansion and contraction of the gases'flowing through the passageways causes an annoying noise, aptly described as motor boating" due toits similarity with the noise of a motor boat exhaust. v I

The external cylindrical surface of the heat exchange casting 42 is provided with a longitudinal groove 18. A plurality of heat conducting fins 66 are pressed over the casting 42, each of these fins having a cylindrical flange 82 engaging the casting forming a means for spacing the fins. These flanges 82 are in snug engagev ment with the outer wall of the'casting 42 so as to form efllcient parts for heat conduction from the casting to the fins. Each of the flanges 62 has a dent 84 formed therein for cooperation with the groove 16 in the casting 42. The fins are thus locked against rotation with respect to the casting.

The manufacture of the die casting 42 with its numerous interconnecting passageways is accomplished in an ingenious manner. Due to the limitations in the die casting operation, it, is not feasible to-form the openings 62a. and 12 which connect the rearward ends of the .various passageways by die core parts which are withdrawn from the forward end of the casting. To obviate this difliculty, the die casting die is provided with four pins conformed to interengage with the portions of the die used for forming the passageways 62 to 66, 69, 10, to form the openings 62a,

12, to the shape best illustrated in. Fig. 5. The withdrawal of the four pins for forming the opening 12 results in leaving four cylindrical openings 86 in internal bosses 88. These openings are closed by means of cylindrical plugs 66,

the ends of which are chamfered and which are secured in position to seal cylindrical openings by swaging or peening material from the made of the v coefficient of expansion and contraction, or they may, if desired be made of cold rolled steel, providing they are carefully swaged in place.

While['leakage past the plugs is undesirable;

and can-readily be prevented, such leakage would not seriouslyinterfere with the operation or safety of the heater, since the passageways in the casting 42 are, whenever the heater is in operation, at subatmosph'eric pressure, and

therefore any leakage would be of atmospheric air into the passageways rather than leakage of gases of combustion to the atmosphere. The plugs, so. are, however, of such size that they have to be pressedinto the bores '6 formed in the bosses 84, such press flt usually assuring that there will be no leakage past the plugs and that the plugs will remain in place. The swaging operation is thus an addedprecaution to assure that the plugs will not become loose or permit leaking of airinto the passageways of the casting. s

ly. past the heat radiating fins by the motor,

driven fan 44.

Since the body of the heat exchange device is essentially a unitary casting, and since the incasting 42 over the outer chamfered ends of the plugs, as indicated inFig. 5. 4

The rearward end of the casting 42 has a projection 92 engaging in a complementary h'ole formed in a mounting plate 94 carrying the switch mechanism 46, the mounting plate being secured to the casting 42 by a bushing 96 threaded in the casting and also forming a guide for the valve stem 34. 4

The casting 42 is preferably made of an'aluminum alloy containing in the order of 95% aluminum and 5% silicon, the plugs being sertion of the plugs 64 is a relatively simple operation, it will be apparent that the body may be very economically produced. Similarly, the assembly of the fins 86 on the casting 42 is a very simple operation, since these fins need merely be pressed over the casting one after another. The

partitions between the various passageways .63 a'nd65, 69, and 16, are of suflicient thickness to provide adequate metal for conduction of heat from the gases flowing through the passageways to the external cylindrical wall of the casting and thence to the heat radiating fins 66. The casting a 42 is of such construction that it may be readily cast without the possibility of having a large proportion of defective castings. Furthermore,

the casting is of arigid and structurally strong shape for the amount of. metal used, contributing to its durability and utilization as a structural part of the heater. While I have shown and described a particular form of my invention, it will be apparent to those skilled in the art that numerous modifications and variations may be made without departing from the underlying principles of the invention. I therefore desire, by the following claims, to include within the scope of my invention all such similar and modified constructions whereby sub-' st'antially the results of the invention may be obtained by substantially the same or equivalent means.

'I claim:

1. A heat exchange device comprising casting having a plurality of interconnected longitudinally extending passageways therein, said passageways opening toward one end only of said casting, said casting having a shoulder formed at the end thereof at which said passageways are open, and a bailie plate pressed against said some alloy-so astohave the aunitary shoulder, said bafile plate covering the ends of said passageways and having an opening for admitting a heating medium to atleast one of said passageways.

y 2. A heat exchange device comprising a unitary casting having a plurality of spaced walls forming interconnected longitudinally extending passageways therein, said passageways opening toward one end only of said casting, said casting having a shoulder formed adjacent the open ends of said passageways, a baffle plate pressed against said shoulder, said baffle plate covering the ends of said passageways, some of the Walls of said passageways having core holes extending from the closed ends of adjacent passageways longitudinally of and intersecting the walls, thereby tance from the closed end of said passageways longitudinally of and intersecting said partitions, thereby forming ports connecting said passageways, and a plurality of plugs secured in said casting to close the open ends of said holes.

THOMAS F. SPACKMAN. 

